BillD wrote:Not much. Bob put a resistor between the voltage source output and the current source output do reduce the damping of the amplifier. He feels that gives an amp a more tubey sound (I call it tubby). What I'm talking about is all about Ohm's law. If you maintain a constant voltage, when the impedance goes down, the current must go up to maintain that constant voltage. With a constant current amplifier, if the impedance goes down, it actually requires less voltage to maintain the constant current.

It follows that the output impedance of a voltage source must be at or very near zero ohms for it to remain constant, assuming varying load impedances (speakers) are connected to it.